Music guide
Frequency to Note: Tuning, Pitch, and Cents Deviation
Convert sound frequencies to musical notes and cents to tune instruments and understand pitch relationships.
Written by James — Founder & Builder, BoringToolsKit · Published 2026 · Planning information, not professional advice.
How frequency maps to pitch
Each doubling of frequency is one octave. Equal temperament divides each octave into 12 equal semitones, so each semitone is a frequency ratio of the 12th root of 2, about 1.05946. A 440 Hz tone is the A above middle C (A4), and 880 Hz is A5.
Cents measure tuning accuracy
A cent is one hundredth of a semitone. A note that is 50 cents sharp sits halfway to the next semitone and will sound noticeably out of tune; most tuners consider a few cents of deviation acceptable. The converter shows exactly how far a measured frequency is from the nearest equal-temperament note.
Tuning workflow
Pluck or sing a note, measure its frequency, and compare it to the expected value. If the reading is sharp or flat by more than a few cents, adjust the instrument. This is especially useful for setting intonation on guitars, tuning pianos, and checking vocal pitch against a reference.